Agents
Graph Neural Ordinary Differential Equations
Often, closed -- form analytic formulations are not available and forecasting or decision making tasks have to rely on noisy, irregularly sampled observations. This class of systems offers a crystal clear example of inductive relational biases. Introducing inductive biases in statistics or machine learning is a well known approach to improving sample efficiency and generalization performance. From the choice of objective function, to the design of ad -- hoc deep learning architectures suited to the specific problem at hand, biases are common and effective. Relational inductive biases [1] represent a special class of biases, concerned with relationship between entities.
Thompson Sampling for Factored Multi-Agent Bandits
Verstraeten, Timothy, Bargiacchi, Eugenio, Libin, Pieter JK, Roijers, Diederik M, Nowรฉ, Ann
Multi-agent coordination is prevalent in many real-world applications. However, such coordination is challenging due to its combinatorial nature. An important observation in this regard is that agents in the real world often only directly affect a limited set of neighboring agents. Leveraging such loose couplings among agents is key to making coordination in multi-agent systems feasible. In this work, we focus on learning to coordinate. Specifically, we consider the multi-agent multi-armed bandit framework, in which fully cooperative loosely-coupled agents must learn to coordinate their decisions to optimize a common objective. As opposed to in the planning setting, for learning methods it is challenging to establish theoretical guarantees. We propose multi-agent Thompson sampling (MATS), a new Bayesian exploration-exploitation algorithm that leverages loose couplings. We provide a regret bound that is sublinear in time and low-order polynomial in the highest number of actions of a single agent for sparse coordination graphs. Finally, we empirically show that MATS outperforms the state-of-the-art algorithm, MAUCE, on two synthetic benchmarks, a realistic wind farm control task, and a novel benchmark with Poisson distributions.
CoverNet: Multimodal Behavior Prediction using Trajectory Sets
Phan-Minh, Tung, Grigore, Elena Corina, Boulton, Freddy A., Beijbom, Oscar, Wolff, Eric M.
We present CoverNet, a new method for multimodal, probabilistic trajectory prediction in urban driving scenarios. Previous work has employed a variety of methods, including multimodal regression, occupancy maps, and 1-step stochastic policies. We instead frame the trajectory prediction problem as classification over a diverse set of trajectories. The size of this set remains manageable, due to the fact that there are a limited number of distinct actions that can be taken over a reasonable prediction horizon. We structure the trajectory set to a) ensure a desired level of coverage of the state space, and b) eliminate physically impossible trajectories. By dynamically generating trajectory sets based on the agent's current state, we can further improve the efficiency of our method. We demonstrate our approach on public, real-world self-driving datasets, and show that it outperforms state-of-the-art methods.
A Measurement of Social Capital in an Open Source Software Project
Alqithami, Saad, Alzahrani, Musaad, Alghamdi, Fahad, Budiarto, Rahmat, Hexmoor, Henry
The paper provides an understanding of social capital in organizations that are open membership multi-agent systems with an emphasis in our formulation on the dynamic network of social interaction that, in part, elucidate evolving structures and impromptu topologies of networks. This paper, therefore, models an open source project as an organizational network. It provides definitions of social capital for this organizational network and formulation of the mechanism to optimize the social capital for achieving its goal that is optimized productivity. A case study of an open source Apache-Hadoop project is considered and empirically evaluated. An analysis of how social capital can be created within this type of organizations and driven to a measurement for its value is provided. Finally, a verification on whether the social capital of the organizational network is proportional towards optimizing their productivity is considered.
A Transfer Learning Method for Goal Recognition Exploiting Cross-Domain Spatial Features
Duhamel, Thibault, Maynard, Mariane, Kabanza, Froduald
The ability to infer the intentions of others, predict their goals, and deduce their plans are critical features for intelligent agents. For a long time, several approaches investigated the use of symbolic representations and inferences with limited success, principally because it is difficult to capture the cognitive knowledge behind human decisions explicitly. The trend, nowadays, is increasingly focusing on learning to infer intentions directly from data, using deep learning in particular. We are now observing interesting applications of intent classification in natural language processing, visual activity recognition, and emerging approaches in other domains. This paper discusses a novel approach combining few-shot and transfer learning with cross-domain features, to learn to infer the intent of an agent navigating in physical environments, executing arbitrary long sequences of actions to achieve their goals. Experiments in synthetic environments demonstrate improved performance in terms of learning from few samples and generalizing to unseen configurations, compared to a deep-learning baseline approach.
Facility Location Problem with Capacity Constraints: Algorithmic and Mechanism Design Perspectives
Aziz, Haris, Chan, Hau, Lee, Barton E., Li, Bo, Walsh, Toby
We consider the facility location problem in the one-dimensional setting where each facility can serve a limited number of agents from the algorithmic and mechanism design perspectives. From the algorithmic perspective, we prove t hat the corresponding optimization problem, where the goal is t o locate facilities to minimize either the total cost to all ag ents or the maximum cost of any agent is NPhard. However, we show that the problem is fixed-parameter tractable, and the optimal solution can be computed in polynomial time whenever the number of facilities is bounded, or when all facilit ies have identical capacities. We then consider the problem fro m a mechanism design perspective where the agents are strategic and need not reveal their true locations. We show that sev - eral natural mechanisms studied in the uncapacitated setti ng either lose strategyproofness or a bound on the solution qua l-ity for the total or maximum cost objective. We then propose new mechanisms that are strategyproof and achieve approximation guarantees that almost match the lower bounds.
Verbal Programming of Robot Behavior
Home robots may come with many sophisticated built-in abilities, however there will always be a degree of customization needed for each user and environment. Ideally this should be accomplished through one-shot learning, as collecting the large number of examples needed for statistical inference is tedious. A particularly appealing approach is to simply explain to the robot, via speech, what it should be doing. In this paper we describe the ALIA cognitive architecture that is able to effectively incorporate user-supplied advice and prohibitions in this manner. The functioning of the implemented system on a small robot is illustrated by an associated video [11]. 1 INTRODUCTION A typical home robot of the future might have built-in navigation, object recognition, task planning, and dexterous manipulation. Y et, despite these sophisticated capabilities, there are still things it cannot know when it first arrives. For instance, what a particular room in the house is called, even if it can identify the general type.
Online Fair Division: A Survey
Aleksandrov, Martin, Walsh, Toby
We survey a burgeoning and promising new research area that considers the online nature of many practical fair division problems. We identify wide variety of such online fair division problems, as well as discuss new mechanisms and normative properties that apply to this online setting. The online nature of such fair division problems provides both opportunities and challenges such as the possibility to develop new online mechanisms as well as the difficulty of dealing with an uncertain future. Introduction Fair division (Brams and Taylor 1996) is an important problem facing society today as increasing economical, environmental, and other pressures require us to try to do more with limited resources. Much previous work in fair division assumes the problem is offline and fixed. That is, we suppose that the agents being allocated resources, and the resources being allocated to these agents are all known and fixed. But practical reality is often quite different (Walsh 2014a; 2015). Fair division problems are often online, with either the agents, or the resources to be allocated, or both not being fixed and potentially changing over time.
Genuine Personal Identifiers and Mutual Sureties for Sybil-Resilient Community Formation
Shahaf, Gal, Shapiro, Ehud, Talmon, Nimrod
While most of humanity is suddenly on the net, the value of this singularity is hampered by the lack of credible digital identities: Social networking, person-to-person transactions, democratic conduct, cooperation and philanthropy are all hampered by the profound presence of fake identities, as illustrated by Facebook's removal of 5.4Bn fake accounts since the beginning of 2019. Here, we introduce the fundamental notion of a \emph{genuine personal identifier}---a globally unique and singular identifier of a person---and present a foundation for a decentralized, grassroots, bottom-up process in which every human being may create, own, and protect the privacy of a genuine personal identifier. The solution employs mutual sureties among owners of personal identifiers, resulting in a mutual-surety graph reminiscent of a web-of-trust. Importantly, this approach is designed for a distributed realization, possibly using distributed ledger technology, and does not depend on the use or storage of biometric properties. For the solution to be complete, additional components are needed, notably a mechanism that encourages honest behavior and a sybil-resilient governance system.
Playing Hide-and-Seek, Machines Invent New Tools
Programmers at OpenAI, an artificial intelligence research company, recently taught a gaggle of intelligent artificial agents -- bots -- to play hide-and-seek. Not because they cared who won: The goal was to observe how competition between hiders and seekers would drive the bots to find and use digital tools. The idea is familiar to anyone who's ever played the game in real life; it's a kind of scaled-down arms race. When your opponent adopts a strategy that works, you have to abandon what you were doing before and find a new, better plan. It's the rule that governs games from chess to StarCraft II; it's also an adaptation that seems likely to confer an evolutionary advantage.